When I use Asymptote to create 3D figures, they appear in the final PDF as static images. When the user hovers the mouse over them, the message "click to activate" is displayed and a mouse click transforms them into rotatable and zoomable interactive figures.

I want to achieve the same thing with my U3D files which I include using movie15:

This figure automatically converts into an interactive figure if the viewer supports it. This is bad if the user opens the document to print it. What parameters do I need to change to introduce the "click to activate behaviour"?